Conventional brakes for motor-driven vehicles involve a single actuating lever, i.e., brake pedal which in turn hydraulically operates individual brake pads at each of the four wheels. However, early automobile braking was done mechanically and a single lever operated the brakes on all of the wheels, however, in some cases there was a mechanical advantage built into the braking system. Conventional braking systems for bicycles and the like usually involve a hand lever on each end of the handle bars such that one hand lever operates the front brake and the other hand lever operates the rear brake, allowing differential pressure to be applied therefor, essentially eliminating the possibility of over braking the front wheel causing a loss of control. Early developments in the braking systems for bicycles produced a braking system wherein if the operator applied excessive pressure to either of the brakes, this braking pressure could be equalized or directed with more pressure to the rear brake, rather than to the front brake.
As technology has progressed and a goal is to allow handicapped persons to have many of the same opportunities as non-handicapped persons, there is seen a need for a single-lever brake operating system which, firstly, incorporates the safety of directing the brake force to the rear wheel with greater force than the front wheel, at least initially, and secondly, permitting the single-lever brake mechanism to apply an equivalent amount of braking force to the brakes themselves as would have been applied had a standard two-hand operated, lever brake system been used.
Prior art references which disclose both the sequencing of brake application and the control thereof include:
U.S. Pat. No. 1,535,092, granted to Bell Apr. 28, 1925, which discloses a single foot pedal mounted brake system for an automobile wherein the service brake is effectively advanced prior to the emergency brake.
U.S. Pat. No. 2,460,204, granted to Vacher Jan. 25, 1949, discloses a brake actuating mechanism within the brake itself, wherein a cam surface controls the rate at which the individual brake pads are applied to the wheel.
U.S. Pat. No. 3,942,609, granted to Hill Mar. 9, 1976, discloses a device wherein, regardless of whether the left or right hand brake is actuated the rear brake of this bicycle is preferentially actuated, utilizing springs, levers and pulleys to provide a bias to resist movement of the front brake actuator.
U.S. Pat. No. 4,057,127, granted to Woodring Nov. 8, 1977, discloses a device which mechanically provides a preference to the rear brake actuator on a bicycle.
U.S. Pat. No. 4,267,746, granted to Pruett May 19, 1981, discloses a single hand-operated actuator for effecting operation of two brakes, i.e., front and rear, and includes a spring bias means within the hand actuator to provide preferential actuation to the rear brake.
U.S. Pat. No. 4,480,720, granted to Shimano Nov. 6, 1984, discloses a device for use with either one or two control levers, wherein the initial braking input provides a proportionately greater force to the rear wheel brake than the front, and thereafter the input is redistributed in a greater proportion to the front.
U.S. Pat. No. 4,582,178, granted to Huneault Apr. 15, 1986, discloses a brake system for a bicycle wherein the tilting of the bicycle seat actuates the brakes.
U.S. Pat. No. 4,644,816, granted to Cockburn Feb. 24, 1987, discloses a brake actuator, including a single mounted handle actuating means wherein the attachment of the brake actuating cables to the actuator determines the order in which the brakes are applied.
U.S. Pat. No. 4,765,443 to Cunningham dated Aug. 23, 1988 discloses a cam actuator for bicycle brakes but utilizes the cam to control the actuation of the brake pads themselves and does not provide for actuation of more than one brake from a single source.
U.S. Pat. No. 4,773,510, granted to Sato Sep. 27, 1988, discloses a pair of hand brakes for a bicycle, each attached to a single actuating member in a physical fashion such that the one brake is preferentially actuated regardless which of the handle members is engaged.